We are investigating those serologic and immunologic processes operative in the etiology and pathogenesis of the rheumatic diseases. We will be studying the nature of the renal lesion of early Systemic Lupus Erythematosus (SLE) through alteration in renal catabolic functions directed toward the light chains of immunoglobulins. We will be studying various complement activating materials present in the sera of patients with SLE. We shall continue studies of the biological functions of anti-gamma globulins.